﻿Rocks, 
  in 
  Littleton, 
  JVew 
  Hampshire. 
  217 
  

  

  Devonian 
  fossiliferous 
  horizon. 
  — 
  The 
  sediments 
  of 
  Blue- 
  

   berry 
  Mt. 
  are 
  less 
  metamorphosed 
  than 
  anywhere 
  else 
  in 
  the 
  

   Ammonoosuc 
  district. 
  With 
  this 
  fact 
  in 
  mind, 
  the 
  writer 
  was 
  

   constantly 
  on 
  the 
  lookout 
  for 
  fossils 
  during 
  his 
  field 
  work 
  in 
  

   this 
  part 
  of 
  the 
  country. 
  In*1911 
  he 
  chanced 
  upon 
  some 
  poorly 
  

   preserved 
  brachiopod 
  impressions 
  in 
  talus 
  at 
  the 
  foot 
  of 
  the 
  

   ' 
  Crags,' 
  a 
  precipice 
  in 
  the 
  dark 
  gray 
  sandstone 
  above 
  the 
  

   banded 
  argillites 
  south 
  of 
  Fitch 
  Hill. 
  The 
  outcrop 
  does 
  not 
  

   come 
  within 
  the 
  bounds 
  of 
  the 
  map. 
  This 
  is 
  probably 
  on 
  the 
  

   south 
  side 
  of 
  the 
  syncline. 
  

  

  The 
  most 
  important 
  discovery 
  was 
  made 
  last 
  summer 
  

   (August, 
  1912) 
  at 
  Loc. 
  25 
  (Sec. 
  D). 
  Here, 
  in 
  a 
  layer 
  of 
  fine 
  

   sandstone 
  not 
  more 
  than 
  two 
  inches 
  thick 
  — 
  one 
  of 
  the 
  light 
  

   gray 
  layers 
  of 
  the 
  banded 
  argillites 
  — 
  were 
  found 
  fifty 
  or 
  sixty 
  

   impressions 
  representing 
  eight 
  or 
  nine 
  species 
  of 
  brachiopods 
  

   and 
  possibly 
  one 
  pelecypod. 
  This 
  harvest 
  was 
  so 
  encouraging 
  

   that 
  careful 
  search 
  was 
  made 
  in 
  the 
  vicinity 
  for 
  more 
  fossilif- 
  

   erous 
  beds, 
  but 
  with 
  no 
  success. 
  Even 
  the 
  one 
  layer 
  that 
  con- 
  

   tained 
  these 
  impressions 
  was 
  barren 
  except 
  within 
  a 
  length 
  of 
  

   about 
  four 
  feet. 
  Subsequently, 
  the 
  banded 
  argillites 
  yielded 
  

   more 
  brachiopod 
  remains 
  at 
  Loc. 
  39, 
  near 
  Young's 
  Pond, 
  

   almost 
  three 
  miies 
  southwest 
  of 
  Loc. 
  25. 
  Some 
  very 
  obscure 
  

   impressions 
  of 
  the 
  same 
  nature 
  were 
  found 
  at 
  Loc. 
  21, 
  on 
  the 
  

   crest 
  of 
  Blueberry 
  Mt. 
  

  

  If, 
  as 
  w 
  T 
  e 
  believe, 
  the 
  exposure 
  at 
  Loc. 
  25 
  is 
  stratigraphically 
  

   directly 
  above 
  the 
  strata 
  of 
  Locs. 
  26 
  and 
  27, 
  and 
  if 
  these 
  latter 
  

   rocks 
  belong 
  to 
  the 
  basal 
  series, 
  allowing 
  for 
  the 
  slope 
  of 
  the 
  

   hill 
  and 
  for 
  the 
  dip, 
  the 
  thickness 
  of 
  the 
  beds 
  between 
  Locs. 
  

   26 
  and 
  25 
  is 
  about 
  2900 
  feet.* 
  It 
  is 
  unfortunate 
  that 
  the 
  

   structure 
  is 
  so 
  doubtful 
  ; 
  but 
  even 
  if 
  Loc. 
  25 
  w 
  r 
  ere 
  on 
  the 
  south 
  

   limb 
  of 
  a 
  fold, 
  it 
  would 
  still 
  be 
  more 
  than 
  3000 
  feet 
  above 
  the 
  

   basal 
  member 
  on 
  the 
  south. 
  This 
  is 
  demonstrated 
  by 
  the 
  

   nearly 
  vertical 
  dips 
  on 
  the 
  southeast 
  slope 
  of 
  Blueberry 
  Mt. 
  

   We 
  are 
  forced 
  to 
  conclude, 
  then, 
  that 
  these 
  fossils 
  come 
  from 
  

   a 
  horizon 
  many 
  hundred 
  feet 
  higher 
  than 
  any 
  of 
  the 
  fossilif- 
  

   erous 
  beds 
  hitherto 
  known 
  in 
  the 
  Ammonoosuc 
  district. 
  

  

  The 
  layer 
  containing 
  the 
  fossils 
  is 
  a 
  hard, 
  tough, 
  medium 
  

   gray, 
  fine-grained 
  sandstone 
  in 
  which 
  a 
  little 
  secondary 
  mica 
  

   has 
  developed, 
  yet 
  not 
  enough 
  to 
  give 
  the 
  rock 
  a 
  cleavage. 
  

   With 
  a 
  hand-lens 
  it 
  is 
  seen 
  to 
  be 
  pitted 
  with 
  small 
  holes, 
  prob- 
  

   ably 
  the 
  casts 
  of 
  some 
  soluble 
  mineral, 
  such 
  as 
  calcite. 
  

  

  *In 
  our 
  notice 
  printed 
  in 
  Science 
  (N. 
  S., 
  xxxvi, 
  p. 
  275, 
  1912), 
  we 
  said 
  that 
  

   the 
  fossiliferous 
  horizon 
  of 
  Loc. 
  25 
  was 
  "'stratigraphically 
  700' 
  or 
  more 
  

   above 
  the 
  Fitch 
  Hill" 
  Niagaran 
  limestone. 
  This 
  estimate 
  was 
  made 
  before 
  

   we 
  had 
  investigated 
  the 
  geology 
  of 
  the 
  hillside 
  below 
  Loc. 
  25. 
  It 
  was 
  

   obtained 
  by 
  adding 
  the 
  thickness 
  of 
  the 
  basal 
  series 
  of 
  Fitch 
  Hill 
  to 
  the 
  

   thickness 
  of 
  the 
  banded 
  argillites 
  below 
  Loc. 
  25. 
  It 
  was 
  obviously 
  very 
  

   conservative. 
  

  

  